This invention relates to the use of an alternating current motor for driving a vehicle closure, and further to control improvements for such systems.
Vehicles have typically included components which are driven by DC motors. This is because the power supply on most vehicles is DC. AC motors have some desirable benefits when utilized in a vehicle application.
More recently, increased voltage batteries are being proposed for vehicles. With an increased voltage, the use of AC motors becomes more practical on a vehicle.
One type of vehicle component which has typically been driven by a DC motor is a vehicle closure. Vehicle closures include windows, sun roofs, moon roofs, etc. Generally, a glass panel is moved within a frame between an open and closed position. One problem with such closures is that occasionally an obstruction will be found in the path of the closure. The obstruction can be created by a passenger""s arm, etc. Upon a closure contacting such an obstruction, it would be desirable that the motor stop or reverse. Complex controls have been developed for identifying such an obstruction.
Moreover, another problem with vehicle component drives is that it would be desirable to utilize a motor which is as small as possible. However, during certain periods of time, higher torque is necessary.
In a disclosed embodiment of this invention, an AC motor is utilized to drive a vehicle closure between open and closed positions. The closure may be a window, a sun roof, a moon roof, etc. The motor is connected through appropriate controls to drive the closure.
In a second feature of this invention, the motor is preferably a three-phase powered motor. The timing of the phase waves is monitored. When driving a closure member to a closed position, occasionally an object, such as a passenger""s arm, may be in the path of the closure. Thus, vehicle designers attempt to identify such objects, and stop operation of the motor if an object is detected. The present invention discloses a control for detecting an object by monitoring the phase spacing between the three-phase power supply. By looking at peaks across the three-phases, and the time spacing between those peaks, a control can identify the presence of an obstruction. When an obstruction is detected, then the control can stop or reverse the motor.
In a further feature of this invention, some way of determining the position of the closure is also utilized. Preferably, a position sensor, or a counter for counting the number of peaks can be utilized such that the control has a reliable feedback of the actual position of the closure. As closure movement begins, and as it approaches an end of travel, one embodiment of this invention varies the frequency to control the speed of the closure. Thus, the closure slows as it approaches an end-of-travel position. Further, the frequency is controlled to provide start-up characteristics which are most desirable. This aspect of the invention can also be utilized for other vehicle components such as a motor for driving a seat, etc.
These and other features of the present invention can be best understood from the following specification and drawings, the following which is a brief description.